Effectiveness and safety of tocilizumab in systemic onset juvenile idiopathic arthritis: a retrospective study in a large pediatric hospital, Tripoli-Libya

Background: Systemic onset juvenile idiopathic arthritis (SoJIA) is the most severe subtype of juvenile idiopathic arthritis (JIA); treatment options are limited. Interleukin-6 plays an important role in remission. Aim: This study aimed to evaluate the effectiveness and safety of Tocilizumab for the treatment of children with SoJIA. Methods: A retrospective, consecutive case series study was conducted at Tripoli Children Hospital. The study involved all cases who were diagnosed as SoJIA in the period from May 2015 to June 2020 who has received Tocilizumab therapy for at least 12 weeks. Besides demographic data, data relevant to effectiveness and safety of the therapy were extracted from medical records. Results: A total of 15 patients were eligible and included in the analysis. The mean age was 10.9 ±3.6 years old, and males accounted for 53.3% of patients. Significant improvement in several clinical manifestations of active SoJIA was reported after 12 weeks post Tocilizumab therapy. The mean number of joints with active arthritis reduced from 5.3± 4.4 to 0.4±=0.7 (p=0.001), and the mean number of joints with limited motion dropped from 3.8±3.10 to 0.8±1.3 (p=0.002). The percentage of patients who had no fever ameliorated to 100% compared to 33.3% only at baseline (p=0.021), and the proportion of patients who had no rash increased from 66.7 to 100% (p=0.032). The median physician’s global VAS score diminished from 6 to 1 (p=0.001). Statistically significant reduction in several laboratory markers of active disease was also reported, for instance, the median ESR decreased from 30 to5 (p=0.001)) and the median CRP dropped from 12 to zero (p=0.016). The reported adverse effects post Tocilizumab were limited and occurred at a low rate, this included gastroenteritis (13.3%) and acute focal pneumonia (13.3%). Neutropenia was the only laboratory abnormality, and was found in one case (6.7%). Conclusion: The overall risk/benefit profile of Tocilizumab used among SoJIA pediatric patients was acceptable, as indicated by the significant practical improvement in clinical symptoms and laboratory findings. This provides further support to previous research findings on the effectiveness of Tocilizumab to treat patients with SoJIA.